Priority is claimed to Japanese Patent Application Number JP2004-193290 filed on Jun. 30, 2004, the disclosure of which is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a circuit device and a manufacturing method thereof, more specifically, to a circuit device including a plurality of wiring layers laminated while interposing an insulating layer, and a manufacturing method thereof
2. Background Art
A configuration of conventional circuit device 100 will be described with reference to FIG. 15. This technology is described for instance in Japanese Patent Publication No. 2001-339151 (p. 1, FIG. 1). FIG. 15 is a cross-sectional view of the conventional circuit device 100.
In the conventional circuit device 100, first conductive pattern 102A is formed on a surface of support substrate 101 and second conductive pattern 102B is formed on a rear surface of the support substrate 101. Moreover, semiconductor element 104 and chip element 106 are fixed onto the first conductive pattern 102A, and the semiconductor element 104 is electrically connected to the first conductive pattern 102A by use of metal thin lines 105. Meanwhile, the first conductive pattern 102A and the elements connected thereto are sealed with sealing resin 103.
In addition, the first conductive pattern 102A formed on the front surface of the support substrate 101 and the second conductive pattern 102B formed on the rear surface of the support substrate 101 are electrically connected to each other through contact holes 108. These contact holes 108 are formed by burying a conductive material into holes, which are formed by penetrating the support substrate 101.
However, the circuit device 100 applies a substrate made of an organic material such as epoxy resin as the circuit substrate 101. The substrate made of the organic material has been applied in light of workability upon formation of the contact holes 108. However, the organic substrate such as a glass epoxy substrate has low thermal conductivity, and therefore has a problem that the substrate cannot discharge heat generated by the embedded elements efficiently to the outside. Moreover, there is also a problem that formation of the contact holes 108 is complicated when resin containing a large amount of inorganic filler is applied as the material of the support substrate 101 in order to enhance a heat radiation performance of the support substrate 101.